<template>
  <el-input v-bind="$attrs" id="getValue" type="textarea" />
  <el-button @click="addInput">添加填空</el-button>
</template>
<script>
export default {
  data(){
    return{
      aaa: ''
    }
  },
  methods: {
    addInput(){
      document.getElementById('getValue').value += '____'
    }
  }
}
</script>